European Patent Application No. 1,989, published May 30, 1979, discloses compounds having the formula ##STR7## wherein the symbols are defined, inter alia, as follows: R.sub.h is hydrogen, m is 0, R.sub.i and R.sub.j are independently hydrogen, alkyl, cycloalkyl, arylalkyl or aryl, n is 1 to 17 and R.sub.k and R.sub.p are independently hydrogen, cycloalkyl, alkyl, arylalkyl, alkoxyalkyl, aryloxyalkyl, hydroxyalkyl, or --Y--NR.sub.q R.sub.r wherein Y is alkyl of 1 to 4 carbons and R.sub.q and R.sub.r are independently hydrogen, alkyl or phenyl.
U.S. Pat. No. 4,105,776, issued Aug. 8, 1978 is representative of a large body of art dealing with mercaptoacylamino acids which are useful for the treatment of angiotensin related hypertension.